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3 Function Construction
3.3 Device and Address
32
FXCPU Structured Programming Manual
(Application Functions)
3.3 Device and Address
Devices can be described in two methods, device method and address method.
Device method
In this method, a device is described using the device name and device number.
Address method
This method is defined in IEC61131-3, and used as shown in the table below.
• Memory area position
The memory area position in which data is assigned is classified into "input", "output" or "internal".
X(X Device method) : I(Input)
Y(Y Device method) : Q(Output)
Any other device : M(Internal)
•Size
The principle of the description method corresponding to the device method (MELSEC description method)
is as follows:
Bit device : X(Bit)
Word device: W(Word (16 bits)), D(Double word (32 bits))
• Classification
The 3rd and later characters indicate the device type which cannot be specified only by the position and
size explained above.
The classification is not required for devices "X" and "Y".
Refer to the following for the device description method:
→ 7.3 Appendix A
Head
1st character:
Position
2nd character: Size
3rd and later characters:
Classification
Number
%
I Input (Omitted) Bit This number is provided for
detailed classification.
Period (.) is used to delimit
the subsequent "Number".
The characters for
classification may be omitted.
This decimal number
corresponds to the device
number.
QOutput X Bit
M Internal W Word (16 bits)
D Double word (32 bits)
L Long Word (64 bits)
X 0 D 100
Device name
Device number
%I X 0 %M X 1 . 863
Memory area
position
Size Classification Numbe
r